RNA interference (RNAi) in mammals is mediated by small interfering RNAs (siRNAs) (Fire et al, Nature 1998, 391:806) or microRNAs (miRNAs) (Ambros, Nature 2004, 431(7006):350-355; Bartel, Cell 2004, 116(2): 281-97). The corresponding process in plants is commonly referred to as specific post-transcriptional gene silencing (PTGS) or RNA silencing and is also referred to as quelling in fungi.
A siRNA is a double-stranded RNA or modified RNA molecule which down-regulates or silences (prevents) the expression of a gene/mRNA of its endogenous (cellular) counterpart. The mechanism of RNA interference is detailed infra.
PCT Publication No. WO 2008/050329 and U.S. Ser. No. 11/978,089 to the assignee of the present invention relate to inhibitors of pro-apoptotic genes, and are incorporated by reference in their entirety. PCT Patent Publication Nos. WO 2008/104978 and WO 2009/044392 to the assignee of the present invention relate to chemically modified siRNA structures, and are incorporated by reference in their entirety.